Network-attached storage (NAS) and storage-area networks (SAN) are widely used applications for storage enclosures. A storage enclosure deployed in a NAS system functions as a node (or server) directly attached to the network (e.g., a LAN) and dedicated to file sharing. A NAS head device operates as an interface between clients on the network and the devices storing the data. The NAS appears on the network as a single node having the IP address of the NAS head device, and clients generally access the NAS head over an Ethernet connection. In contrast, a SAN is a dedicated network of shared storage devices separate from the client network (e.g., the LAN). The Fibre Channel protocol interconnects these storage devices, from which clients access data in blocks.
Important to the reliable operation of NAS and SAN storage systems is the ability to monitor and control the storage enclosures remotely. Enclosure management is the process of gathering information regarding the operating status of the enclosures within the storage system. Such information includes the temperature of the enclosure, fan speed, and the operational status of the power supplies, of the interconnections between the various components of the enclosure, and of the enclosure cards. Managers of a storage system can access this management information remotely from an external entity, e.g., a remote host computer.
Storage enclosures can gather management information in one of two ways: “in-band” and “out-of-band.” In-band enclosure management employs a storage processor to collect the management information for reporting to the remote host. This management technique relies on the storage processor to be operational. Failure of the storage processor negatively affects enclosure management. For out-of-band enclosure management, a separate component in the enclosure other than the storage processor collects and forwards the management information to the remote host. This technique removes this reliance on the storage processor to be operational for enclosure management.
The manner in which a storage enclosure collects management information can depend upon the particular application of the enclosure. For example, a supplier of storage products can configure its NAS enclosures to perform out-of-band enclosure management and its SAN enclosures to perform in-band enclosure management. Because NAS uses different hardware and software than SAN and out-of-band management functionality requires different hardware and software components than in-band management, often NAS enclosures differ significantly in shape, size, and content from SAN enclosures. To support both types of enclosure management, this supplier of storage products would need to manage different sets of chassis and component inventories for the different enclosure types. Costs are thus higher to support the separate enclosure types.